Sealing system for fill pipe head

ABSTRACT

Sealing system for fuel tank fill head which comprises:
         a shutter ( 1 ) that can be moved between an open position, in which fuel may be introduced into the fill pipe, and a closed position in which the fill pipe is closed, the shutter ( 1 ) passing from one position to another under the effect of the thrust exerted by a filling nozzle ( 62, 64 );   a shield ( 7 ) that is placed upstream of the shutter ( 1 ) and that can be moved between an open position, in which the shutter ( 1 ) is accessible, and a closed position in which the shutter ( 1 ) is protected from the atmosphere by the shield ( 7 ); and   a nozzle inhibitor designed so as to only allow opening of the shutter ( 1 ) when a filling nozzle head of predefined diameter ( 62, 64 ) comes into contact with the nozzle inhibitor.       

     The nozzle inhibitor is integrated into the shield ( 7 ).

The present invention relates to a sealing system for a fuel tank fill pipe.

The fill pipes present in fuel tanks, in particular the tanks aboard motor vehicles, are sealed during normal use of the tank, outside the filling periods. The sealing is generally achieved either by means of a cap or by means of a sealing system integrated into the fill pipe, often called a “capless” system.

Improved versions of capless systems generally comprise a shutter and a protective shield. Thanks to the protective shield the shutter is protected and inaccessible. In order to allow access to the fill pipe when filling a tank, the user uses a filling nozzle and brings it into contact with the shield so as to move it to an open position allowing access to the shutter and therefore the filling of the tank itself.

Moreover, fuel tanks are generally intended to contain a single type of fuel, for example diesel or unleaded petrol. So as to avoid filling a tank intended to contain one type of fuel using a nozzle intended for filling with another type of fuel, nozzle inhibitors have been developed.

Nozzle inhibitors based on the diameter of the head of a filling nozzle are known.

In general, the pipe head comprises a guide for the nozzle which serves as a petrol/diesel nozzle inhibitor, i.e. a guide whose geometry makes it impossible to introduce a diesel nozzle head into the fill pipe of a petrol tank. Such a device depends on the geometry of the pipe head and cannot therefore be standardized to all pipe heads.

Improved nozzle inhibitors have been developed. Thus, Patent Application EP 1 625 964 discloses a sealing system for a fill head comprising a protective shield, a nozzle inhibitor and a shutter. The nozzle inhibitor comprises two activator parts with inclined sides able to be moved apart under the effect of the thrust of a filling nozzle and which are coupled to two blocking parts. When a large diameter nozzle (generally this is a diesel-type nozzle) is introduced into the sealing system, this nozzle acts on the two activator parts which move the blocking parts: access to the pipe is then possible for the filling nozzle. On the other hand, when a small diameter nozzle (generally corresponding to a nozzle intended for filling with petrol) is introduced, the two blocking parts are not moved by the activator parts and introduction of the nozzle is prevented. The nozzle inhibitor is positioned between the protective shield and the shutter and is coupled to the shutter. It is consequently not visible to the user so that the user can introduce a nozzle into the fill head upto the vicinity of the shutter. If the filling nozzle is not suitable, i.e. does not correspond to the type of fuel intended for the tank to be filled it will not be able to be introduced beyond the nozzle inhibitor but the user will nevertheless be able to fill the space in the fill head, between the shield and the shutter, with fuel.

One object of the invention is to overcome the disadvantage of the above system. In particular, the aim of the invention is to provide a sealing system which comprises a nozzle inhibitor visible to the user and which prevents an unsuitable filling nozzle from being introduced into the fill head beyond the protective shield.

For this purpose, the invention relates to a sealing system for a fuel tank fill head comprising:

-   -   a shutter that can be moved between an open position, in which         fuel may be introduced into a fill pipe, and a closed position         in which the fill pipe is closed, the shutter passing from the         closed position to the open position under the effect of a         thrust exerted by a filling nozzle head;     -   a shield placed upstream of the shutter and that can be moved         between an open position, in which the shutter is accessible,         and a closed position in which the shutter is protected from the         atmosphere by the shield; and     -   a nozzle inhibitor designed so as to only allow movement of the         shutter from its closed position to its open position when the         nozzle inhibitor has come into contact with a filling nozzle         head having a predefined diameter, when this is introduced into         the fill head,         characterized in that the nozzle inhibitor is integrated into         the shield.

Within the context of the invention, the fill head comprises a longitudinal axis which approximately corresponds to the axis for introducing the filling nozzle into the fill head.

The shutter makes it possible to close the fill pipe of the fuel tank. In a “capless” type system, the shutter takes the place of the conventional closure cap screwed onto the pipe head by the user. The opening and closing of the fill pipe are generally respectively controlled by the opening and closing of a fuel trap door, for example by a connecting rod mechanism or by a train of gears and of pinions. A seal is generally joined to the shutter so as to enable leaktight closure of the fuel tank, thus avoiding contamination of the atmosphere by liquid or gaseous fuel.

The fuel trap door can be moved between an open position allowing access to the fill head and a closed position in which it is generally located in the extension of the body.

The system according to the invention comprises a shield placed upstream of the shutter and that can be moved between an open position, in which the shutter is accessible, and a closed position in which the shutter is protected from the atmosphere by the shield. In its closed position, the shield prevents the even partial introduction of fuel or of any other liquid (for example a jet of pressurized water in the case of cleaning the vehicle) into the fill head. The shield makes it possible to protect the seal and the mechanics around the shutter from dust or any other contamination, thus ensuring the proper operation of the shutter.

According to the invention, the shield is different from the fuel trap door and is located underneath this so that the trap door is upstream of the shield.

Within the context of the invention, it is understood to define that a first component is upstream of a second component when the first component is above the second component relative to the direction for introducing a filling nozzle into the fill pipe.

Advantageously, the shield is prestressed in its open position by elastic return means, for example a torsion spring.

According to the invention, the sealing system also comprises a nozzle inhibitor which is designed so as to only allow movement of the shutter from a closed position to an open position when the nozzle inhibitor has come into contact with a filling nozzle head having a predefined diameter. The expression “nozzle head having a predefined diameter” is understood to denote a nozzle head having a diameter which allows the nozzle to be introduced into the fill head, the fuel that the nozzle is capable of delivering corresponding to the appropriate fuel for filling the tank. In other words, in the case of a diesel tank, the shutter is only accessible by means of a diesel-type nozzle and, in the case of a petrol tank, the shutter is only accessible by means of a petrol-type nozzle.

The nozzle inhibitor is integrated into the shield. Within the context of the invention, the expression “integrated device” is understood to denote a nozzle inhibitor which is located on a face of the shield oriented towards the atmosphere.

The sealing system therefore allows access to the fill pipe by introduction of a filling nozzle suitable for the type of fuel in the fuel tank.

Also advantageously, the shield is kept in its closed position by the nozzle inhibitor and is capable of being moved from its closed position to its open position when the foolprooofing device has come into contact with the filling nozzle head of predefined diameter.

Preferably, the sealing system comprises a locking device capable of locking the shutter in its closed position. Any locking device known in the field of fill head sealing systems may be suitable. A bayonet device is preferred within the context of the invention.

In particular, the locking device may be activated by the opening/closing of the fuel trap door, for example by means of a connecting rod mechanism or by a train of gears and of pinions.

Also preferably, the sealing system comprises a second locking device capable of locking the shield in its closed position. The locking device may, for example, consist of a bayonet device.

The sealing system according to the invention may be in various embodiment forms.

According to a first embodiment, the shield comprises two plates that can be rotated, each respectively about an axis of rotation substantially parallel to the longitudinal axis of the fill head. When the shield is in its closed position, the two plates cooperate so as to prevent the passage of a filling nozzle whereas when the shield is in its open position, the two plates have freed the access to the shutter.

Preferably, each plate is constrained in its open position by an elastic return means such as, for example, a torsion spring.

More preferably, a first plate is constrained in its open position by an elastic return means whereas a second plate is entrained by a rotational movement of the first plate, the two plates each having a surface portion whose respective profiles cooperate together so as to transmit a movement from the first plate to the second plate. The two plates may, for example, cooperate through parts equipped with a toothed profile.

In the particular case where the sealing system according to this embodiment comprises a locking device of bayonet type, the sealing system may be adapted so that, when the bayonet device has passed from an unlocked position to a locked position, the shield has been brought back from its open position to its closed position and is locked.

According to this embodiment, the nozzle inhibitor is placed upstream of the shield and comprises a release and one, or even two, foolproof fingers.

The release is equipped with a profiled part capable of being engaged by a nozzle head so as to be moved in a direction substantially perpendicular to the longitudinal axis of the fill head under the effect of the thrust form the nozzle head engaged with the profiled part.

The nozzle inhibitor also comprises one, or even two, foolproof fingers which are positioned between the shield and the release. The foolproof fingers can only be moved under the effect of the force exerted by a filling nozzle head having a predefined diameter, when this head is engaged with the profiled part of the release and is moved in a direction substantially perpendicular to the longitudinal axis of the fill head. The nozzle inhibitor is designed so as to only allow movement of the shield from its closed position to its open position when the release and the foolproof finger or fingers are moved by a movement of the nozzle head. According to this embodiment, the foolproof finger or fingers are equipped with a holding member which cooperates with a raised part on at least one of the shield plates. In this way, when the foolproof finger or fingers are moved by the nozzle head of suitable diameter, the holding member no longer cooperates with the raised part so that the shield plates are no longer held in the closed position of the shield and, therefore, under the effect of elastic return means, the plates are moved and occupy a position corresponding to the open position of the shield.

When the filling nozzle head has a diameter that is smaller than the dimensions of the profiled part, the nozzle head may be engaged with the profiled part and the release may be moved by a movement of the nozzle head in a direction substantially perpendicular to the longitudinal axis of the fill head. However, if the diameter of the nozzle head is smaller than the predefined diameter, the nozzle head does not engage with the foolproof finger or fingers during its movement and moving the shield to its open position is not possible. Consequently, it is not possible to introduce the nozzle into the fill head.

When the filling nozzle head has a diameter that is larger than the dimensions of the profiled part, the nozzle head cannot be engaged with the profiled part and the release cannot be moved by a movement of the nozzle head in a direction substantially perpendicular to the longitudinal axis of the fill head. Consequently, it is not possible to introduce the nozzle into the fill head either. This is generally the situation which arises when the user tries to introduce a diesel nozzle into a petrol fill head.

Moving the shield is therefore only possible when the diameter of the filling nozzle head has a predefined diameter.

According to a second embodiment of the invention, the nozzle inhibitor comprises a foolproofing pin that can be moved into the path of the filling nozzle head when the nozzle is introduced into the fill head.

Within the context of the invention, the foolproofing pin generally comprises a profiled part which can be engaged by a filling nozzle head of predefined diameter.

Preferably, the nozzle inhibitor comprises a plurality of foolproofing pins arranged so that the shield is capable of being moved from its closed position to its open position when all the pins have come into contact with and are moved by the filling nozzle head.

Preferably, each pin comprises an inclined face and is designed so as to be rotated around an axis substantially parallel to the longitudinal axis of the fill head under the effect of a force exerted by the filling nozzle head when it comes into contact with all the inclined faces, the pins being arranged so that the surfaces projected from the inclined faces over a plane substantially perpendicular to the longitudinal axis of the fill head are contained between two imaginary circles, the respective diameters of which define a range that includes a diameter approximately corresponding to the predefined diameter of the filling nozzle head.

Advantageously, each of the pins comprises an upper face that extends from the face inclined radially towards the outside. During the introduction of a filling nozzle having a diameter smaller than the predefined diameter, the nozzle head cannot contact all the pins and swinging back of the shield is not possible. The introduction of a petrol nozzle into a fill pipe of a diesel tank is thus avoided. During the introduction of a filling nozzle having a diameter larger than the predefined diameter, the nozzle head presses on the upper face of the pins and cannot contact all the inclined faces of the pins. Moving the shield is therefore not possible. The introduction of a diesel nozzle into a fill pipe of a petrol tank is thus avoided.

Preferably, the shield comprises a plate that can be rotated about an axis substantially parallel to the longitudinal axis of the fill head.

More preferably, the shield comprises two plates that can each be rotated respectively about an axis, the axes being merged or being arranged at a short distance from one another so that the plates cooperate and prevent access to the shutter when the shield is in the closed position and that the plates allow access to the shutter when the shield is in its open position.

More preferably still, the shield is formed by a plurality of plates, each plate being able to be rotated about an axis, the axes being arranged equidistantly over a perimeter around the fill pipe opening.

In the case of the second embodiment of the sealing system according to the invention, each pin is preferably firmly attached to one plate of the shield, for example by moulding as one part or by any known means for attaching a pin to the plate.

DESCRIPTION WITH THE AID OF FIGS. 1 TO 33

Other particular aspects and features of the invention will become apparent from the description of a few advantageous embodiments presented below, by way of illustration, with reference to the appended drawings which show:

FIG. 1: exploded view of a sealing system according to the prior art;

FIG. 2: sealing system according to a 1^(st) aspect of the invention;

FIGS. 3-6: shield according to the 1^(st) aspect of the invention;

FIGS. 7-31: sealing system according to a 2^(nd) aspect of the invention;

FIG. 32: cut through the shield from FIG. 18 suitable for a petrol tank;

FIG. 33: cut through the shield from FIG. 18 suitable for a diesel tank.

A “capless” type sealing system for a filling pipe head of a fuel tank is generally represented, as an exploded view, in FIG. 1. Such a system comprises a shutter 1, a support 2 for a bayonet ring 3 intended to be connected to a slider 4, itself intended to be connected to an axle 5 intended for connection with a fuel trap door 6. FIG. 1 also shows a shield 7 and a return spring 8 for the shield 7 intended to cooperate with a push button 9 equipped with a spring 10, and also a connecting rod 11 that enables the return spring 8 to be compressed or decompressed. The other parts illustrated in FIG. 1 are used to connect and/or protect the active components of the system and comprise a cover 12 bearing the shutter 1, a filling bowl 13 attached to the head using a flange 14, and attachment components formed, for example, from clips 15 and screws 16. Generally, the opening/closing of the fuel trap door 6 entrains the opening/closing of the shutter 1. The opening/closing operating mode is known per se from Application WO 2005/025913 and is not described in detail in the present patent application.

The present invention relates to a sealing system similar to that from FIG. 1, comprising the shield 7 and a nozzle inhibitor that makes it possible to avoid introducing a filling nozzle that is unsuitable for the type of fuel tank.

A sealing system according to a first embodiment of the present invention is illustrated in FIGS. 2 to 6. The nozzle inhibitor comprises a release 20 on the upper face of the shield 7. The release 20 is mounted so as to be moveable in a direction (represented by the arrow 22) substantially perpendicular to the longitudinal axis of the fill head. For this purpose, the release 20 comprises a profiled part 24 large enough to be engaged with a filling nozzle head having a predefined diameter. A movement, in the direction 22, of the filling nozzle, the head of which is engaged with the profiled part 24, leads to the movement of the release 20 in the direction 22. The movement of the release 20 allows the disengagement of a holding member (not represented) coupled to the release 20 and cooperating with the shield 7 so that the shield 7 is moved towards its open position under the effect of elastic return means 38. The dimensions of the profiled part 24 of the release 20 are chosen so at to allow the engagement of a nozzle head having a predefined diameter and to avoid the engagement of a nozzle head having a diameter greater than the predefined diameter. Since a nozzle head having a greater diameter cannot be engaged with the profiled part 24, the release 20 cannot be moved under the effect of the thrust exerted by the introduction of such a nozzle and movement of the shield 7 into its open position is not possible. Thus, for example, the introduction of a diesel nozzle into a fill pipe designed for a petrol tank is rendered impossible.

According to one preferred embodiment, illustrated in FIGS. 4 to 6, the nozzle inhibitor moreover comprises a foolproof finger 26 positioned between the shield 7 and the release 20. The foolproof finger 26 is placed in the path of the nozzle head when the latter is moved in the direction of movement 22. When the nozzle head comes into contact with the finger 26 and moves it, the shield 7 can be moved to its open position under the effect of elastic return means 38, for example by the disengagement of a holding member 28 coupled to the finger 26 and to the shield 7. The finger 26 is sized and arranged so as to be moved by a nozzle head having a predefined diameter and to avoid the engagement of a nozzle head having a diameter less than the predefined diameter. Since a nozzle head having a smaller diameter slides along the finger 26 and cannot move it, moving the shield 7 to its open position is not possible. Thus, the introduction of a petrol nozzle into a fill pipe designed for a diesel tank is rendered impossible.

The combined use of the finger 26 and the release 20 makes it possible to avoid introducing nozzles of which the head has a diameter greater than the predefined diameter and nozzles of which the head has a diameter smaller than the predefined diameter into the fill pipe.

The release 20 and the finger 26 are prestressed in a direction opposite to the release direction 22 by means of return springs, 30 and 32 respectively.

The shield 7, as illustrated by FIGS. 3 to 6, is formed by two plates 34, 34′ that can each be moved about an axis of rotation (36 and 36′ respectively, substantially parallel to the longitudinal axis of the fill head and arranged at a short distance from one another). A return spring 38 is coupled to the plate 34 and makes it possible to swing the plate 34 into its open position during the disengagement of the holding member 28. The plates 34, 34′ are connected together by a gear 40 that makes it possible to transmit the movement from the plate 34 to the plate 34′.

A second embodiment of the sealing system according to the invention is illustrated in FIGS. 7 to 33.

FIGS. 7 to 11 represent overviews of a fill pipe comprising a fuel trap door 6, a filling bowl 13 and a sealing system according to the invention. The sealing system comprises a shutter 1 (of the pivoting flap type) equipped with a bayonet-type locking device 3.

FIG. 7 illustrates the situation where the fuel trap door 6 is in an intermediate position between a closed position and an open position. A guard 67 protects the components (68, 68′) which create the connection between the fuel trap door 6 and the sealing system. The components (68, 68′) form a slider type system.

As illustrated in FIGS. 8 and 9 (fuel trap door 6 in closed position) and in FIGS. 10 and 11 (fuel trap door 6 in open position), the connection components (68, 68′) communicate a movement from the fuel trap door 6 to the bayonet 3 so that, when the fuel trap door 6 is open, the bayonet 3 is moved to a position for unlocking the shutter 1 and that, when the fuel trap door 6 is closed, the bayonet 3 is moved to a position for locking the shutter 1.

FIG. 12 represents an exploded view of the fill head. In addition to the components already described above, FIG. 12 illustrates a set of gears and pinions 65 intended to transmit a movement from the trap door 6 to the connection components (68, 68′), a ring 51, plates 52 which form the shield 7, torsion springs 52′, a retaining ring 53, a support 57, two seals 59 and 63 and a spacer 61.

The shield 7 comprises four plates 52 mounted on the support 57, itself clipped to the spacer 61. The spacer 61 is attached to the filling bowl 13. FIGS. 13 and 14 respectively represent a bottom view and a top view of one of the four plates 52. In particular, in FIG. 14, the plate 52 comprises an axis of rotation 54, a guide boss 54′, a foolproofing pin 50 comprising an upper face 55 and an inclined face 56.

According to this embodiment, the moveable pins 50 are positioned in the path of the filling nozzle head.

Each plate 52 can be moved around an axis of rotation 54 substantially parallel to the longitudinal axis of the fill head. A return spring (not shown) is coupled to each plate 52 and makes it possible to move the plate 52 to an open position so that, when the four plates 52 are moved to their open position, access to the shutter 1 is possible. Each pin 50 is firmly attached to a plate 52 and extends from its edge radially in the direction of the centre of the shield 7. As illustrated in FIG. 18, each pin 50 is arranged so that the projection of its inclined face 56 in the plane of the plate 52 with which it is firmly attached is between two imaginary circles 58 and 58′, the respective diameters of which define a range comprising the diameter of a filling nozzle head suitable for the type of fuel tank. In the case of FIG. 18, when the four inclined faces 56 of the four pins 50 are simultaneously contacted by a nozzle head having a predefined diameter, the four plates 52 are moved to their respective open position, represented by the arrows 60 and access to the shutter 1 is made possible.

The arrangement of the inclined faces 56 makes it possible to ensure that the plates 52 of the shield 7 can only be moved to an open position by the introduction of a filling nozzle of which the head has a predefined diameter corresponding to the type of fuel suitable for the tank.

The bottom view of a plate 52 such as illustrated in FIG. 13 shows a locking recess 54″ whose function will be explained below, and also the axis of rotation 54.

The ring 51 forms, for the shield 7, a locking device that operates on the principle of a bayonet. This is because the ring 51 can be rotated and may be moved by a slide pin 68 so that when the trap door 6 is open, the ring 51 is moved to an unlocked position of the shield 7 and when the trap door 6 is closed the ring 51 is moved to a locked position of the shield 7. Activation of the ring 51 is concomitant to the activation of the bayonet 3 for the shutter 1 so that the locking/unlocking of the shutter 1 and of the shield 7 occurs simultaneously and under the action of a movement of the trap door 6.

The ring 51 comprises four ramps 51′ which each cooperate with a guide boss 54′ of a plate 52. When the ring 51 is in the locked position (FIG. 16), the guide bosses 54′ each cooperate with an associated profiled part of the ramp 51′, so that the four plates 52 are kept in a locked position and cannot be moved under the action of a nozzle head coming into contact with the pins 50.

FIG. 17 illustrates the locked position of the shield 7 seen from below. In this figure, the retaining ring 53 comprises semi-rigid tabs 53′ which each cooperate with a locking recess 54″ of a plate 52.

FIGS. 19 to 22 illustrate the unlocked position of the shield 7, no filling nozzle having been introduced.

This position is obtained when the trap door 6 has been opened, driving the movement of the slide system 68, 68′ and the rotation of the ring 51. The guide bosses 54′ no longer cooperate with the ramps 51′. The tabs 53′ cooperate with the locking recesses 54″ so that the plates 52 are kept in their closed position whereas the shield 7 is unlocked. In this position, the user may, for example, clean the filling bowl 13 using a high-pressure water jet without risk of spraying inside the fill pipe.

FIGS. 23 and 24 correspond to the situation where the user brings a filling nozzle of predefined diameter close to the shield 7 so as to move the shield 7 to an open position. The nozzle comes into contact with the inclined faces 56 of the pins 50 so as to exert a force over all the pins 50 and move the plates 52 to their open position by rotation around their respective axis of rotation 54. Once the plates 52 are in their open position, the tabs 53′ are released from the recesses 54″ (FIG. 25).

Moreover, the torsion springs 52′ in this embodiment (FIGS. 26 and 27) have a geometry such that they push back the plates 52 until they are fully open so that the shield 7 does not constitute an obstacle to the introduction of the filling nozzle.

FIG. 28 illustrates a top view of the fill head, in the open position of the shield 7.

FIGS. 29 to 31 illustrate the closure steps of the sealing system.

After opening the shield 7, the guide bosses 54′ cooperate with the ramps 51′ of the ring 51 (FIG. 29) so that when the trap door 6 is reclosed, the ring 51 is moved to a locked position, driving the plates 52 of the shield 7, the guide bosses 54′ are moved along the ramps 51′ and the shield 7 is reclosed (FIGS. 30 and 31).

The foolproofing of the sealing system according to the second embodiment of the invention may also be illustrated by referring to FIGS. 32 and 33.

FIG. 32 shows a system suitable for a petrol tank. A cross section through two opposite plates 52 is represented. Each plate 52 is firmly attached to a pin 50 having an inclined face 56 and an upper face 55. The projections of the inclined faces 56 over a plane of the associated plates 52 are between two imaginary circles 58 and 58′ defining a range that comprises the diameter of a suitable petrol nozzle. Thus, a petrol nozzle head 62 may simultaneously come into contact with all the inclined faces 56 so as to enable the movement of the shield 7 to its open position. On the other hand, a diesel nozzle head 64, having a larger diameter than the petrol nozzle head 62, cannot simultaneously contact all the inclined faces 56 but can only come into contact with some of the inclined faces 56, or even with the upper faces 55. Thus, the movement of the shield 7 coupled to a petrol tank is only possible by introduction of a petrol nozzle.

FIG. 33 shows a system suitable for a diesel tank. The projections of the inclined faces 56 over a plane of the associated plates 52 are between two imaginary circles, the respective diameters of which define a range that comprises the diameter of a suitable diesel nozzle. Thus, a diesel nozzle head 64 may simultaneously come into contact with all the inclined faces 56 so as to enable the movement of the shield 7 under the effect of introducing the diesel nozzle. On the other hand, a petrol nozzle head 62, having a smaller diameter than the diesel nozzle head 64, cannot simultaneously contact all the inclined faces 56. This is because the petrol nozzle head 62 comes into contact with a lower level 66 formed by the plate 52 and optionally with one of the inclined faces 56. Thus, the shield 7 coupled to a diesel tank can only be moved to its open position by the effect of introducing a diesel nozzle. 

1. A sealing system for fuel tank fill head comprising a shutter (1) that can be moved between an open position, in which fuel may be introduced into a fill pipe, and a closed position in which the fill pipe is closed, the shutter (1) passing from the closed position to the open position under the effect of a thrust exerted by a filling nozzle head; a shield (7) placed upstream of the shutter (1) and that can be moved between an open position, in which the shutter (1) is accessible, and a closed position in which the shutter (1) is protected from the atmosphere by the shield (7); and a nozzle inhibitor designed so as to only allow movement of the shutter (1) from its closed position to its open position when the nozzle inhibitor has come into contact with a filling nozzle head (62,64) having a predefined diameter, when this is introduced into the fill head, wherein the nozzle inhibitor is integrated into the shield (7).
 2. The sealing system according to claim 1, wherein the shield (7) is prestressed in its open position by elastic return means.
 3. The sealing system according to claim 1, wherein the shield (7) is kept in its closed position by the nozzle inhibitor and is capable of being moved from its closed position to its open position when the nozzle inhibitor has come into contact with the filling nozzle head (62,64).
 4. The sealing system according to claim 1, wherein the nozzle inhibitor is placed upstream of the shield (7) and comprises a release (20) equipped with a profiled part (24) and one, or even two, foolproof fingers (26) positioned between the shield (7) and the release (20) so as to enable movement of the shield (7) from its closed position to its open position when the release (20) and the foolproof finger (26) are moved under the effect of the thrust exerted by the filling nozzle head (62, 64) when it is engaged with the profiled part (24) and is moved in a direction substantially perpendicular to the longitudinal axis of the fill head.
 5. The sealing system according to claim 1, wherein the nozzle inhibitor comprises a foolproofing pin (50) that can be moved into the path of the filling nozzle head (62,64) when the nozzle is introduced into the fill head.
 6. The sealing system according to claim 5, wherein the nozzle inhibitor comprises a plurality of foolproofing pins (50) arranged such that the shield (7) is capable of being moved from its closed position to its open position when all the pins (50) have come into contact with and are moved by the filling nozzle head (62, 64).
 7. The sealing system according to claim 6, wherein each pin (50) comprises an inclined face (56) and is designed so as to be rotated around an axis substantially parallel to the longitudinal axis of the fill head under the effect of a force exerted by the filling nozzle head (62,64) when it comes into contact with all the inclined faces, the pins (50) being arranged so that the surfaces projected from the inclined faces (56) over a plane substantially perpendicular to the longitudinal axis of the fill head are contained between two imaginary circles (58, 58′), the respective diameters of which define a range that includes a diameter approximately corresponding to the predefined diameter of the filling nozzle head (62, 64).
 8. The sealing system according to claim 1, wherein the shield (7) comprises a plate (34, 52) that can be rotated about an axis (36, 54) substantially parallel to the longitudinal axis of the fill head.
 9. The sealing system according to claim 8, wherein the shield (7) comprises two plates (34, 34′) that can each be rotated respectively about an axis (36, 36′), the axes (36, 36′) being merged or being arranged at a short distance from one another so that the plates (34, 34′) cooperate and prevent access to the shutter (1) when the shield (7) is in the closed position and that the plates (34, 34′) allow access to the shutter (1) when the shield (7) is in its open position.
 10. The sealing system according to claim 8, wherein the shield (7) is formed by a plurality of plates (52), each plate (52) being able to be rotated about an axis (54), the axes (54) being arranged equidistantly over a perimeter around the fill pipe opening.
 11. The sealing system according to claim 5, wherein each pin (50) is firmly attached to one plate (52) of the shield (7). 